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Canine distemper is a contagious, febrile disease of canids and other carnivores caused by Canine Distemper Virus. Canine distemper virus is a member of the Paramyxoviridae family and the morbillivirus genus. The Paramyxoviridae have a helical nucleocapsid surrounded by an envelope which possesses spiked glycoproteins responsible for haemagglutinin, neuraminidase and haemolytic activities. The genome of the Paramyxoviridae is single-stranded, negative-sense RNA which is used as a template for the production of messenger (positive-sense) RNA and further genomic material. Paramyxoviridae are sensitive to heat, dessication and most disinfectants, and so are not resistant in the environment. The Paramyxovididae family is divided to two sub-families, the Paramyxovirinae and the Pneumovirinae. It is within the Paramyxovirinae sub-family that morbilliviruses fall, along with respiroviruses, henipaviruses, rubulaviruses and avulaviruses. As well as canine distemper virus (CDV), the morbilliviruses include rinderpest, peste de petits ruminants, measles, phocine distemper and dolphin distemper.

Canine distemper is a contagious, febrile disease of canids and other carnivores caused by Canine Distemper Virus. Canine distemper virus is a member of the Paramyxoviridae family and the morbillivirus genus. The Paramyxoviridae have a helical nucleocapsid surrounded by an envelope which possesses spiked glycoproteins responsible for haemagglutinin, neuraminidase and haemolytic activities. The genome of the Paramyxoviridae is single-stranded, negative-sense RNA which is used as a template for the production of messenger (positive-sense) RNA and further genomic material. Paramyxoviridae are sensitive to heat, dessication and most disinfectants, and so are not resistant in the environment. The Paramyxovididae family is divided to two sub-families, the Paramyxovirinae and the Pneumovirinae. It is within the Paramyxovirinae sub-family that morbilliviruses fall, along with respiroviruses, henipaviruses, rubulaviruses and avulaviruses. As well as canine distemper virus (CDV), the morbilliviruses include rinderpest, peste de petits ruminants, measles, phocine distemper and dolphin distemper.

      

      

Canine distemper virus is spread by direct and indirect contact via ingestion or inhalation of aerosolised droplets. Initial infection of the nasal cavity, pharynx and lungs is followed by a macrophage-associated viraemia to local lymph nodes where the virus replicates. Within one week, all lymphoid tissue is infected, causing lymphopenia. A second viraemic stage then distributes the virus to the surface epithelium of the respiratory, gastrointestinal and urogenital tracts, endocrine tissue and the grey and white matter of the CNS.  A biphasic pyrexia is typical of distemper infection: the first fever occurs 3-6 days post-infection and is associated with lymphopenia, and the second peak coincides with widespread viraemia. Further signs depend on both the virus strain and the immune response mounted. In the event of a strong humoral and cellular response, disease may remain subclinicals, and if a weak immune response is mounted infection is generally subacute. If the immune response fails, acute death occurs 2-4 weeks post-infection, commonly due to convulsions or other CNS disturbances. When clinical disease manifests, this is initially characterised by lethargy, dehydration, anorexia, and weight loss followed by more specific signs depending on the principally affected organ.

Canine distemper virus is shed in all excretions and secretions, and is spread by direct and indirect contact via ingestion or inhalation of aerosolised droplets. Initial infection of the nasal cavity, pharynx and lungs is followed by a macrophage-associated viraemia to local lymph nodes where the virus replicates. Within one week, all lymphoid tissue is infected, causing lymphopenia. A second viraemic stage then distributes the virus to the surface epithelium of the respiratory, gastrointestinal and urogenital tracts, endocrine tissue and the grey and white matter of the CNS.  A biphasic pyrexia is typical of distemper infection: the first fever occurs 3-6 days post-infection and is associated with lymphopenia, and the second peak coincides with widespread viraemia. Further signs depend on both the virus strain and the immune response mounted. In the event of a strong humoral and cellular response, disease may remain subclinicals, and if a weak immune response is mounted infection is generally subacute. If the immune response fails, acute death occurs 2-4 weeks post-infection, commonly due to convulsions or other CNS disturbances. When clinical disease manifests, this is initially characterised by lethargy, dehydration, anorexia, and weight loss followed by more specific signs depending on the principally affected organ.

==Signalment==

==Signalment==